1. Field of the Invention
The present invention refers to a handling module for a coating apparatus as well as a coating apparatus for depositing at least one, preferably two or more layers on a substrate and a method for coating a substrate in such a coating apparatus.
2. Prior Art
In modern technology and industry coating processes are very important, since a lot of products comprise coatings or layers which have to be applied on the products or substrates. For example, displays for television apparatuses or computer monitors may comprise a plurality of layers which have to be applied on a glass substrate. This is especially true for so-called OLED-displays, monitors or television screens, which comprise organic light emitting diodes. These organic light emitting diodes are composed of a plurality of layers which are deposited one after the other. In order to have separate pixels which can be activated independently, layers have to be structured or patterned. In order to achieve a structure or pattern, masks are used during the coating process. Accordingly, different masks for different layers have to be used and during the production process the masks have to be arranged and removed from the substrate for several times.
Another application for organic light emitting diodes is their use in lighting devices. The fabrication is less complex compared to display technology, since the different RGB (Red Green Blue)—layers do not have to be offset to each other. Nevertheless, several thin layers have to be deposited.
EP 17 173 39 A2 discloses a continuously working in-line coating apparatus in which a substrate to be coated is travelling along a coating path, the substrate being coated with different layers or treated by corresponding pre- or after-treatments. Along the coating path having a transport path for the substrates included therein rotation modules are provided for, which allow to transfer the substrate to a mask-exchange station and to transport back the masks to the beginning of a specific coating section so as to be re-used for a new substrate. Due to the in-line design of such an apparatus, a very effective coating of the substrates can be achieved. However, such an apparatus requires lot of space for the coating path and the transport paths of the masks.
Another apparatus for manufacturing an organic electroluminescence display is disclosed in US 2002/0187265 A1. According to this concept, a lot of coating sections for depositing single layers are disposed one after the other, while each of the coating sections comprise one central handling chamber with a transfer robot and adjacent coating and treatment chambers around the handling chamber. Such a design may save some space and therefore the space requirements are reduced, however, due to separate chambers for preparing the substrate before coating, still huge space is required for such an apparatus. Moreover, a great number of transfer steps by the transfer robot with respect to the surrounding treatment and coating chambers make such a coating apparatus not very effective for mass production.
A mixed concept for a continuous and discontinuous transport through an in-line coating apparatus is disclosed in DE 102 05 167 C5. According to this concept, a rotation module is disposed at the end of a continuously working conveyor transporting the substrates through vacuum coating chambers. Since the rotation module comprises several retainers for receiving substrates, the rotation module may act as a buffer chamber for disrupting continuous transport. However, additional buffer chambers can lead to even more required space.
WO 2007/038427 A2 discloses a method and an apparatus for electronic device manufacture using shadow masks with a continuous in-line design. According to this apparatus, a plurality of deposition vessels are arranged one after the other and every deposition vessel has at least two shadow masks associated therewith. The two masks can be alternately positioned for patterning the deposition material during deposition and for cleaning in adjacent cleaning vessels. Thus, throughput can be increased, but the required space is also increased.